技術標籤：notificationandroidframework

文章目錄

• 前言
• notify（）判斷是否block的流程
• 關閉應用傳送notification的介面setNotificationsEnabledForPackage

前言

本文基於android8.1環境。主要是分析setNotificationsEnabledForPackage介面遮蔽應用傳送notification的功能實現原理。

notify（）判斷是否block的流程

從notifymanager開始：

    public void notify(String tag, int id, Notification notification)
 

    {
        notifyAsUser(tag, id, notification, new UserHandle(UserHandle.myUserId()));
    }

    /**
     * @hide
     */
    public void notifyAsUser(String tag, int id, Notification notification, UserHandle user)
    {
        INotificationManager service = getService();
        String pkg = mContext.
 
getPackageName();
        // Fix the notification as best we can.
        Notification.addFieldsFromContext(mContext, notification);
        if (notification.sound != null) {
            notification.sound = notification.sound.getCanonicalUri();
            if (StrictMode.vmFileUriExposureEnabled()) {
 

                notification.sound.checkFileUriExposed("Notification.sound");
            }
        }
        fixLegacySmallIcon(notification, pkg);
        if (mContext.getApplicationInfo().targetSdkVersion > Build.VERSION_CODES.LOLLIPOP_MR1) {
            if (notification.getSmallIcon() == null) {
                throw new IllegalArgumentException("Invalid notification (no valid small icon): "
                        + notification);
            }
        }
        if (localLOGV) Log.v(TAG, pkg + ": notify(" + id + ", " + notification + ")");
        notification.reduceImageSizes(mContext);
        ActivityManager am = (ActivityManager) mContext.getSystemService(Context.ACTIVITY_SERVICE);
        boolean isLowRam = am.isLowRamDevice();
        final Notification copy = Builder.maybeCloneStrippedForDelivery(notification, isLowRam);
        try {
            service.enqueueNotificationWithTag(pkg, mContext.getOpPackageName(), tag, id,
                    copy, user.getIdentifier());
        } catch (RemoteException e) {
            throw e.rethrowFromSystemServer();
        }
    }

在這裡

        try {
            service.enqueueNotificationWithTag(pkg, mContext.getOpPackageName(), tag, id,
                    copy, user.getIdentifier());
        } catch (RemoteException e) {
            throw e.rethrowFromSystemServer();
        }

調到NotificationManagerService的enqueueNotificationWithTag

        @Override
        public void enqueueNotificationWithTag(String pkg, String opPkg, String tag, int id,
                Notification notification, int userId) throws RemoteException {
            enqueueNotificationInternal(pkg, opPkg, Binder.getCallingUid(),
                    Binder.getCallingPid(), tag, id, notification, userId);
        }

    void enqueueNotificationInternal(final String pkg, final String opPkg, final int callingUid,
            final int callingPid, final String tag, final int id, final Notification notification,
            int incomingUserId) {
        if (DBG) {
            Slog.v(TAG, "enqueueNotificationInternal: pkg=" + pkg + " id=" + id
                    + " notification=" + notification);
        }
        checkCallerIsSystemOrSameApp(pkg);

        final int userId = ActivityManager.handleIncomingUser(callingPid,
                callingUid, incomingUserId, true, false, "enqueueNotification", pkg);
        final UserHandle user = new UserHandle(userId);

        if (pkg == null || notification == null) {
            throw new IllegalArgumentException("null not allowed: pkg=" + pkg
                    + " id=" + id + " notification=" + notification);
        }

        // The system can post notifications for any package, let us resolve that.
        final int notificationUid = resolveNotificationUid(opPkg, callingUid, userId);

        // Fix the notification as best we can.
        try {
            final ApplicationInfo ai = mPackageManagerClient.getApplicationInfoAsUser(
                    pkg, PackageManager.MATCH_DEBUG_TRIAGED_MISSING,
                    (userId == UserHandle.USER_ALL) ? UserHandle.USER_SYSTEM : userId);
            Notification.addFieldsFromContext(ai, notification);

            int canColorize = mPackageManagerClient.checkPermission(
                    android.Manifest.permission.USE_COLORIZED_NOTIFICATIONS, pkg);
            if (canColorize == PERMISSION_GRANTED) {
                notification.flags |= Notification.FLAG_CAN_COLORIZE;
            } else {
                notification.flags &= ~Notification.FLAG_CAN_COLORIZE;
            }

        } catch (NameNotFoundException e) {
            Slog.e(TAG, "Cannot create a context for sending app", e);
            return;
        }

        mUsageStats.registerEnqueuedByApp(pkg);

        // setup local book-keeping
        String channelId = notification.getChannelId();
        if (mIsTelevision && (new Notification.TvExtender(notification)).getChannelId() != null) {
            channelId = (new Notification.TvExtender(notification)).getChannelId();
        }
        final NotificationChannel channel = mRankingHelper.getNotificationChannel(pkg,
                notificationUid, channelId, false /* includeDeleted */);
        if (channel == null) {
            final String noChannelStr = "No Channel found for "
                    + "pkg=" + pkg
                    + ", channelId=" + channelId
                    + ", id=" + id
                    + ", tag=" + tag
                    + ", opPkg=" + opPkg
                    + ", callingUid=" + callingUid
                    + ", userId=" + userId
                    + ", incomingUserId=" + incomingUserId
                    + ", notificationUid=" + notificationUid
                    + ", notification=" + notification;
            Log.e(TAG, noChannelStr);
            doChannelWarningToast("Developer warning for package \"" + pkg + "\"\n" +
                    "Failed to post notification on channel \"" + channelId + "\"\n" +
                    "See log for more details");
            return;
        }

        final StatusBarNotification n = new StatusBarNotification(
                pkg, opPkg, id, tag, notificationUid, callingPid, notification,
                user, null, System.currentTimeMillis());
        final NotificationRecord r = new NotificationRecord(getContext(), n, channel);

        if ((notification.flags & Notification.FLAG_FOREGROUND_SERVICE) != 0
                && (channel.getUserLockedFields() & NotificationChannel.USER_LOCKED_IMPORTANCE) == 0
                && (r.getImportance() == IMPORTANCE_MIN || r.getImportance() == IMPORTANCE_NONE)) {
            // Increase the importance of foreground service notifications unless the user had an
            // opinion otherwise
            if (TextUtils.isEmpty(channelId)
                    || NotificationChannel.DEFAULT_CHANNEL_ID.equals(channelId)) {
                r.setImportance(IMPORTANCE_LOW, "Bumped for foreground service");
            } else {
                channel.setImportance(IMPORTANCE_LOW);
                mRankingHelper.updateNotificationChannel(pkg, notificationUid, channel, false);
                r.updateNotificationChannel(channel);
            }
        }

        if (!checkDisqualifyingFeatures(userId, notificationUid, id, tag, r,
                r.sbn.getOverrideGroupKey() != null)) {
            return;
        }
        …………
    }

在最後這裡調到：

    /**
     * Checks if a notification can be posted. checks rate limiter, snooze helper, and blocking.
     *
     * Has side effects.
     */
    private boolean checkDisqualifyingFeatures(int userId, int callingUid, int id, String tag,
            NotificationRecord r, boolean isAutogroup) {
		…………
        // blocked apps
        if (isBlocked(r, mUsageStats)) {
            return false;
        }

        return true;
    }

再走到

    protected boolean isBlocked(NotificationRecord r, NotificationUsageStats usageStats) {
……
        final boolean isBlocked =
                mRankingHelper.getImportance(pkg, callingUid) == NotificationManager.IMPORTANCE_NONE
                || r.getChannel().getImportance() == NotificationManager.IMPORTANCE_NONE;
        if (isBlocked) {
            Slog.e(TAG, "Suppressing notification from package by user request.");
            usageStats.registerBlocked(r);
        }
        return isBlocked;
    }

調到RankingHelper的getImportance：

    @Override
    public int getImportance(String packageName, int uid) {
        return getOrCreateRecord(packageName, uid).importance;
    }
    
    private Record getOrCreateRecord(String pkg, int uid) {
        return getOrCreateRecord(pkg, uid,
                DEFAULT_IMPORTANCE, DEFAULT_PRIORITY, DEFAULT_VISIBILITY, DEFAULT_SHOW_BADGE);
    }

    private Record getOrCreateRecord(String pkg, int uid, int importance, int priority,
            int visibility, boolean showBadge) {
        final String key = recordKey(pkg, uid);
        synchronized (mRecords) {
            Record r = (uid == Record.UNKNOWN_UID) ? mRestoredWithoutUids.get(pkg) : mRecords.get(
                    key);
            if (r == null) {
                r = new Record();
                r.pkg = pkg;
                r.uid = uid;
                r.importance = importance;
                r.priority = priority;
                r.visibility = visibility;
                r.showBadge = showBadge;

                try {
                    createDefaultChannelIfNeeded(r);
                } catch (NameNotFoundException e) {
                    Slog.e(TAG, "createDefaultChannelIfNeeded - Exception: " + e);
                }

                if (r.uid == Record.UNKNOWN_UID) {
                    mRestoredWithoutUids.put(pkg, r);
                } else {
                    mRecords.put(key, r);
                }
            }
            return r;
        }
    }

關閉應用傳送notification的介面setNotificationsEnabledForPackage

        @Override
        public void setNotificationsEnabledForPackage(String pkg, int uid, boolean enabled) {
            checkCallerIsSystem();

            mRankingHelper.setEnabled(pkg, uid, enabled);
            // Now, cancel any outstanding notifications that are part of a just-disabled app
            if (!enabled) {
                cancelAllNotificationsInt(MY_UID, MY_PID, pkg, null, 0, 0, true,
                        UserHandle.getUserId(uid), REASON_PACKAGE_BANNED, null);
            }
            savePolicyFile();
        }

從這裡調到RankingHelper的setEnabled：

    @Override
    public void setImportance(String pkgName, int uid, int importance) {
        getOrCreateRecord(pkgName, uid).importance = importance;
        updateConfig();
    }

    public void setEnabled(String packageName, int uid, boolean enabled) {
        boolean wasEnabled = getImportance(packageName, uid) != NotificationManager.IMPORTANCE_NONE;
        if (wasEnabled == enabled) {
            return;
        }
        setImportance(packageName, uid,
                enabled ? DEFAULT_IMPORTANCE : NotificationManager.IMPORTANCE_NONE);
    }